Depth control for plows



July 3, 1962 N. o. BRQETZMAN ETAL 3,042,121

DEPTH CONTROL FOR FLOWS Filed DeG. l5, 1955 IN V EN TORS 3,042,121 Patented July 3, 1962 3,042,121 DEPTH CONTROL FOR PLUWS Norton 0. Broetzrnan, Oconto Falls, and August E. Elfe, Suring, Wis., assignors of one-third to Howard W. Eslien, Oconto Falls, Wis.

Filed Dec. 15, 1955, Ser. No. 553,364 2 Claims. (Cl. 172-239) The present invention relates generally to improvements in the art of farming, and relates more particularly to the provision of an improved device for controlling and regulating the cutting depth of plows.

A primary object of this invention is to provide an improved depth control apparatus for plows which is extremely simple, compact and durable in construction and which is moreover highly eicient and practical in actual use.

In the farming industry, it is customary practice to till the soil with the aid of a tractor drawn plow which may be adjusted to the proper plowing depth by means of a manually operable power unit con-trollable by the tractor operator. However, due to frequent irregularities in the terrain being Worked, it is ordinarily necessary to constantly carefully watch the plowshares at great inconvenience to the operator and to effect frequent adjustments in the depth setting of the plowshares by means of the power control unit so as to cut resultant furrows of constant depth. This is, of course, a difficult, tedious land time consuming task; and while some attempts have heretofore been made to provide means lfor automatically regulating the cutting depth of a trailing plow While compensating for irregularities in the terrain, such devices have not enjoyed widespread commercial acceptance for `one reason or another.

It is therefore a more specific object of our present invention to provide an improved automatically operable depth control `device for plows which obviates all of the objections and disadvantages attendant prior devices intended for like purposes.

Another specific object of the invention is to provide an improved depth control device for plows which is adapted to be readily adjusted lfor a desired plowing depth and which functions to automatically maintain the plowshares at the desired depth regardless of irregularities in the terrain.

Another specic object of our invention is to provide an improved device for automatically controlling the cutting depth of plows and in which provision is made for permitting the plowshares to rise over obstructions while returning the `same automatically to the desired depth when past the obstruction.

Still another specific object of our present invention is to provide an improved automatically responsive and readily adjustable depth control for plows wherein shock is effectively absorbed to minimize wear and tear on the plowshares, t

An additional specific object of this invention is to provide an improved depth control device for plows which consists of relatively few parts and which is readily applicable either as an accessory `or attachment to existing units or which may be incorporated directly in the plow assemblage as produced by the manufacturer or supplier. t t

A further specic object of the present invention is to provide an improved depth control device for a vehicle drawn plow comprising, a ground-engaging member mounted on the frame of the plow for movement to various positions of elevation relative to the plowshares, a reciprocable depth control member coupled to the ground engaging member to normally establish the plowing depth, the control member being subjected to uid pressure on its opposite sides, and a pair of reversely functioning fluid pressure relief elements communicating with the opposite sides of the control member.

These and other `specific objects and advantages of Kthe present improvements will become apparent from the fol lowing detailed description.

A clear conception of the several features constituting the present invention, and of the mode of constructing and of utilizing typical depth control devices embodying the improvements, may be had by referring to the drawing accompanying and forming a part of this speciiication wherein like reference characters designate the same or similar parts in the various views.

FIG. 1 is a 4moresor-less diagrammatic fragmentary side view of :a typical plow coupled to the rear of -a tractor and having one of the improved depth control devices associated therewith;

FIG. 2 is a somewhat enlarged fragmentary part-sectional side view of the improved control and `shockabsorbing mechanism; and

FIG. 3 is a similarly enlarged fragmentary top View of the main control cylinder and its associated parts.

While the invention has been particularly lshown and described herein as being especially applicable to a tractor drawn plow of a particular type with the main control ram or plunger and the shock-absorbing elements being housed in separate cylinders, it is not desired or intended to thereby unnecessarily limit or restrict the scope or utility thereof since the device may be applied to -any vehicle drawn implement of similar character with the several cylinders being combined in a single unitary housing as desired; and it is also contemplated that certain specific descriptive terms used herein shall be given xthe broadest possible interpretation consistent with the disclosure.

Referring to the drawing `and particularly FIG. 1 thereof, the improved device has been shown therein as being associated with a plow, designated generally by the numeral 5, coupled in a suitable manner as at 6 to the rear of a tractor 7. While the plow 5 has been more-orless diagrammatically illustrated, the essential elements thereof are generally a main frame 8, one. or more rear transporting wheels 9, a plurality of 'spaced furrow digging plowshares 10, and `a draw or draft -link 11. The powered vehicle or tractor 7, only a portion of which has likewise been diagrammatically shown for purposes of illustration, comprises generally, a main frame 13 lsupported on front wheels, not shown, and rear wheels 14 powered in the usual manner by a suitable gas engine or power plant, not shown, a draft bar 12 coupled to the linls'` 11 of the tractor, a drivers seat 15, suitable `steering apparatus, likewise not shown, and the usual engine driven iluid pump 16. p

The improved depth control device comprises, in general, a ground engaging member shown herein as a wheel 1S carried at the lower end of a lever or bell crank arm 19 the upper end of which is swingably mounted as at 2t) on the frame 8 of the plow to permit swinging movement thereof to various positions of elevation relative to the plowshares 10; a depth control member which may be in the form of a piston 21, FIGJ2, reciprocably confined within cylinder 22 also mounted on the plow frame 8 as by a pivotal connection 23, the piston 21 having a rod 24 projecting from one end of the cylinder 22 and coupled with the bell crank arm 25 so as to swing the arm 19 about the pivot 26 upon reciprocation of the piston 21; means such as the sets of flexible fluid pressure lines or conduits Z7, 23 and '29, 30 respectively communicating with the pump 16 past a control valve 31 and leading to opposite ends of the cylinder 22 for subjecting the opposite sides of the control member or piston 21 to predetermined fluid pressure as determined by the setting of the valve 31 and its control lever 32; and a pair of reversely functioning fluid pressure relief elements or dashpots 33, 34 communicating with the cylinder 22 on opposite sides of the piston 21 as by way of the conduits 27, 23 respectively.

Each of the fluid pressure relief elements 33, 34 consists of a receiver or cylinder communicating at one end with the respective conduits 27, 28 through suitable connections 36, 37 respectively, and each of these receivers has a piston 38', 39 respectively therein urged under predetermined resilient pressure as by springs 48, 4'1 respectively, the pressure in each of the dashpots or receivers 33, 34 being adjustable by means of threaded caps 42, 43 respectively upon which the springs are seated. lt is also preferable to provide means for limiting the stroke of the piston 211 within the cylinder 22, and in the present instance, this is accomplished by means of a pair of rods 45, 46 each having a series of notches 47, 48 respectively and each being secured at one end to the piston rod 24 as by means of a crosshead 49 for travel with the piston 21 and its rod 24, each of the rods 45, 46 also having a pair of spaced rings 50, 51 respectively each provided with a set screw cooperable with the respective series of notches 47, 48 to permit adjustment of the rings to different positions and the rings being cooperable with fixed lugs 52, 53 projecting laterally from the cylinder 22 to thereby limit movement of the piston 21 within predetermined limits. The control valve 31 is preferably mounted at a location convenient to the operator of the vehicle 7 and this valve may be of any suitable type adapted to regulate the fluid pressure to the cylinder 22 by way of the conduits 27, 28, and the pump `16 is of the usual type driven by the power take-olf or directly by the motor of the vehicle '7, and receives oil from the reserve box 54 by way of the line 36 and conveys the same under pressure through the line 29 past the valve 31 for distribution thereby. The conduits 27, 28 are preferably flexible so as to permit ready distortion thereof as the tractor and plow are driven over irregular terrain and to also permit uncoupling of the plow unit from the tractor and convenient storage of the pressure lines 27 28 when not in use.

In operation, the plow is first coupled to the tractor 7 and the lines or conduits 27, "28 are coupled to the cylinder 22 in an obvious manner. The tractor is then started thereby driving the pump 16, and the wheel 18 of the depth control mechanism is adjusted to the proper height for plowing by operation of the valve 31 and the lever 32'which regulates the iiuid pressure to the opposite sides of the piston 21. As the piston 21 is reciprocated to the proper position as controlled by the valve 31, the arms 25, 19 of the bell crank are rotated about the pivot 20 by means of the piston rod 24 so as to properly position the wheel 18 to permit the plowshare to cut into the earth a given distance. After setting, the tractor plow assemblage may be `driven over the desired area, and the wheel 18 will maintain the entire plow frame and the plowshare l at the proper depth for plowing, the wheel 18 riding over the unplowed portion of the terrain in close proximity to the plowshare 10. If an obstruction should be hit by one or more of the plowshares 10, the

shock will be transmitted to the piston 211 through the ground engaging wheel 18, lever arms 19, 25 and the piston rod 24, and the piston 21 will be permitted to momentarily reciprocate in either a forward or reverse direction against the pressure built up to one or the other sides of the piston within the cylinder 22', the liuid being displaced by movement of the piston escaping into one or the other of the dashpots 33, 34. It is believed obvious that the dashpots or iiuid pressure relief elements compensate for displacement of the fluid from one or the other sides of the piston 21 within the cylinder 22 against the action of the springs 40, 41 respectively and as soon as the plow has passed the obstruction, the plowshares l@ are immediately returned to normal plowing depth by action of the compensating dashpots 33, 34 with the pistons 38, 39 respectively thereof returning to normal automatically by action of the springs 40, 41.

From the foregoing detailed description, it is believed apparent that the present invention contemplates provision of an improved depth control device for a vehicle drawn plow which is, in fact, simple and durable and in which shocks are eectively absorbed by the compensating dashpots communicating with the opposite sides of the piston 211. The normal plowing depth may be conveniently controlled from the tractor '7 upon manipulation of the valve control lever 32 which should be located in proximity to the seat 15 and if the plowshare 10 should hit hidden obstructions, the shock will be effectively absorbed as hereinabove described by the relief elements communicating with the cylinder 22 as by way of the conduits 27, 28. The stroke of the piston 21 may be readily adjusted so as to be limited within a predetermined range by means of the adjustment rings carried by the rods 45, 46 and cooperating with the shoulders 52, 53 respectively on the cylinder end head 55. The pressure against which the pistons 33, 39 within the respective dashpots 33, 34 are adapted to act may be regulated by adjusting the threaded elements 42, 43 respectively, and the pistons may be guided in the respective dashpots by means of the rods 56, 57 projecting through the elements 42, 43. The improved devices may be readily manufactured and applied to either existing or new plow units, and these devices consist of relatively few parts, all of which are readily accessible for inspection, replacement or repair. The improved devices have proven highly satisfactory and successful in actual use and the compensating relief elements or dashpots 33, 34 may, of course, be incorporated within a unitary housing with the main cylinder 22.

It should be understood that it is not desired to limit this invention to the exact details of construction or mode of operation herein shown and described, since various modifications within the scope of the appended claims may occur to persons skilled in the art to which this invention pertains.

We claim:

l. A `depth control device for a vehicle drawn plow comprising, a ground `engaging member mounted on the frame of the plow for movement to various positions of elevation relative to the plowshare, a hydraulic cylinder mountedon the plow frame, a piston reciprocable within said cylinder and having a rod extending therefrom and coupled to said ground engaging member to position the same and normally establish the plowing depth, said piston being subjected to a controllable source of fluid pressure on its opposite sides, adjustable means mounted on said piston rod for .movement therewith and cooperable with said cylinder for limiting the reciprocable movement of said piston between two positions, and a pair of reversely functioning fluid pressure relief elements cornmunicating with the opposite sides of said control member.

2. A depth control device for a vehicle drawn plow comprising, a ground engaging member mounted on the frame of the plow for movement to various positions of elevation relative to the plowshare, a hydraulic cylinder also mounted on the plow frame, a piston reciprocable Within said cylinder and having a rod extending therefrom coupled to said ground engaging member to position the same relative to the plowshare, means for subjecting the opposite sides of said piston to a predetermined hydraulic pressure to establish the normal plowing depth, a pair of arms carried by said piston rod and extending along opposite sides of said cylinder, said arms each having a pair of limit stops adjustable therealong and cooperable with said cylinder for fixing the limits of travel of said piston and rod in opposite directions, and a pair of adjustable re- Versely functioning shock-absorbing dashpots communicating with the opposite sides of said piston for momentarily receiving uid displaced under abnormal pressure from the respective side-s thereof.

References Cited in the file of this patent UNITED STATES PATENTS 452,742 Welch May 19, 1891 612,324 Frazier et al Oct. 1l, 1898 10 2,249,402 Stefano July 15, 1941 2,392,006 Silver Jan. 1, 1946 2,393,324 Joy Ian. 22, 1946 2,442,306 McCormick May 25, 1948 2,545,573 Fletcher Mar. 20, 1951 

